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Impact of Bti on Odonata abundance, Poulin et al. 2016

PostPosted: Thu Feb 18, 2016 2:47 pm
by Thomas Weitzel
Jakob C. & Poulin B. 2016. Indirect effects of mosquito control using Bti on dragonflies and damselflies (Odonata) in the Camargue. Insect Conservation and Diversity (2016) doi: 10.1111/icad.12155

Recently published, this study presumes impact of Bti-treatment in coastal reed marshes on species diversity and abundance of drogonflies and damselflies through foodweb cascades.
The authors conclude a dramatic impact of Bti-treatments on the foodweb, with emphasis on chironomid reduction.
The conclusions are based on an obviously incomplete assessment of environmental biotic and abiotic factors, surrounding of study areas as well as odonate biology and behaviour. As previously in the house martin study (Poulin et al. 2010), the treated areas are located closed to the coastline, with a potentially high impact of salinity (control of Ochlerotatus caspius). The diversity of surrounding areas seems to be poor, dominated by salines. In contrast, the control areas are located more in the inner land, presumably more influenced by freshwater input (Rhone, ground water), and surrounded by more terrestrial, natural and various agricultural areas.
This study should be precisely analysed and the far-reaching conclusions of the authors should be evaluated referring to at least the aspects mentioned above and also to relevant literature.